アルミニウム合金拘束多層溶接における曲げ変形挙動

抄録

The present study examines the mechanism of bending distortion during multi-layer welding of restrained butt joint in aluminium heavy plate. The experiments were performed to observe the reaction force, bending moment, deflection of plate and strain distribution during or after welding. Moreover, a theoretical consideration based on the theory of plates was applied to these results and effects of factor on the bending distortion were discussed. The main results are as follows.
The transient deflection during the welding of each pass changes according to the bending moment roughly in a such way that the deflection mode is concave at weld side during heating cycle and convex during cooling cycle. The bending distortion depends upon the reaction force, its eccentricity from the neutral plane of base plate and the plastic deformation. The effects of reaction force and of its eccentricity are remarkable for the first passes and the effect of plastic deformation unevenly distributed in the thickness direction appears for later passes. The bending deflection of plate decreases as the throat thickness increases and as the restrained length decreases. The plastic strain results from the restraint of thermal expansion of plate and from the bending deflection during welding, and its distribution is nearly linear from top face to bottom face. By applying the theory of plate to these specimens, the bending moment and inherent angular deformation of throat are calculated from the measured value of the reaction force, its eccentricity and bending moment of the welded plate, and the effects of eccentricity and inherent angular deformation upon the bending moment of the throat are predicted.